The present invention relates to a valve of a type suitable for periodic filling a fuel storage vessel. More particularly, this invention relates to a improved fill valve for external or internal threaded connection with a standard control valve mounted on a propane use tank. The fill valve of the present invention may control propane flow from a flexible hose extending from a large storage tank to the control valve and then to the smaller propane use tank. The fill valve may be closed and disconnected from the control valve without discharging significant amounts of propane to the environment.
Propane tanks have long been used for home heating and cooking, and for limited commercial and industrial applications. The standard propane use tank includes a control valve for controlling the flow of propane from the use tank to a regulator and then to the fuel burner. To periodically refill the propane use tank, a large propane storage vessel is either transported to the propane use tank, or the propane use tank is transported to the large storage vessel. In either case, the propane use tank is conventionally filled by disconnecting the regulator and interconnecting a fill valve at the end of the flexible hose to the control valve mounted on the propane tank. The fill valve includes an elongate discharge nose for mated interconnection with threads internal of the control valve, and positions the fill valve handle outside a tank guard ring. Once the fill valve has been fluidly connected to the control valve, both the fill valve and the control valve are opened for releasing the pressurized propane from the large storage vessel to the propane use tank.
In order to reduce the time required to fill the propane use tank, the fill valve flow passageway is configured so that is does not substantially restrict the fluid flow from the flexible fill line to the propane use tank. The fill valve preferably is also of the type which may be reliably used by relatively inexperienced personnel. Preferably the fill valve is of quick-acting type with a handle which pivotably moves with respect to the valve body to move the stem from an opened position to a closed position. The fill valve is thus connected to the control valve, the operator pivots the handle to the opened position and quickly fills the propane use tank, then returns the handle to the closed position and disconnects the fill valve from the control valve.
A significant problem with the prior art propane fill valves is that the fill valve seat is spaced substantially from the end of the elongate discharge nose which is interconnected with the control valve. Accordingly, after the propane use tank is refilled and the fill valve and control valve are closed, propane in the elongate nose between the fill valve seat and the control valve seat is discharged to the environment when the fill valve is threadably disconnected from the control valve. In excess of 27 cc of pressurized propane is commonly released in a refilling operation, with the released pressurized propane expanding hundreds of times when vaporizing in the air. The cost of the discharged propane is nominal compared to the significant environmental impact caused by thousands of propane filling operations occurring daily in many locations. Also, the discharged propane may adversely affect the safety of the propane filling operator and others located in the vicinity of the filling operation.
Another significant problem with prior art propane fill valves is that the fill valve comprises a number of threadably interconnected subassemblies which, under pressure, are prone to release propane during the filling process and contribute to numerous environmental and safety hazards.
Yet another problem with prior art fill valves is the relatively high cost of manufacturing the fill valve. Components exposed to high wear are preferably manufactured from a more expensive material, such as stainless steel, while other components are preferably manufactured from lower cost grades of steel.
The disadvantages of the prior art are overcome by the present invention, and an improved fill valve suitable for filling a propane use tank with an externally or internally threaded standard control valve mounted thereon is hereinafter disclosed.
The fill valve of the present invention may be used to reliably control the filling of a propane use tank with a conventional control valve mounted thereon. The fill valve may include a quick acting pivot handle which axially moves a valve stem between the opened and the closed positions. A coil spring conventionally biases the fill valve closed. The fill valve also includes an elongate discharge nose for insertion into the control valve after the regulator has been removed. In one embodiment, an external left hand thread is provided at the discharge end or nose tip of the elongate nose for mating connection with a corresponding internal thread within the interior of the control valve. In another embodiment, an internally threaded nose tip housing is provided around the nose tip for mating connection with a corresponding externally threaded control valve. The fill valve may include a nose tip with an elastomeric external seal mounted thereon for reliable sealing engagement with a seat within the interior of the control valve. Propane flows in the annulus between the elongate nose and the valve stem, and is discharged through an aperture in the nose tip so as not to substantially restrict the flow of propane when the fill valve is in the opened position. The valve stem may extend from the pivot handle through the fill valve body and substantially through the elongate discharge nose. An elastomeric seal may be provided on the end of the valve stem for reliable sealing engagement with a seat. In one embodiment, the seat is formed separate from the nose tip.
It is an object of the invention to provide an improved fill valve of the type which may be used for filling a fluid tank. The fill valve of the present invention may include an elongate discharge nose with an external seal provided on the nose tip for sealing with a seat in a convention control valve. Alternatively, a surface on the nose tip may engage a seal provided in the control valve. The fill valve seal and seat are positioned closely adjacent the discharge end of the fill valve. The fill valve may thus be connected to the control valve mounted on the fluid use tank, and very little fluid is discharged to the environment when the fill valve is removed from the control valve.
It is another object of the invention to provide an improved fill valve with a elongate discharge nose, nose tip and nose tip housing surrounding the nose tip such that the fill valve may be threadably connected to a control valve mounted on the propane use tank. In one embodiment, the fill valve is designed for engagement with internal pocket threads in the control valve. In another embodiment, the fill valve is designed to be secured to external threads on the control valve.
Yet another object of the present invention is providing an improved technique for manufacturing and assembling a fill valve to provide a highly reliable valve with a lower manufacturing cost. According to one embodiment, an elongate sleeve is permanently interconnected with a seat member to form a sleeve-seat subassembly, and a discharge housing is thereafter positioned over the sleeve-seat subassembly. A nose tip is thereafter permanently secured to a lower end of the sleeve-seat subassembly, and a valve stem is positioned through the valve body and the sleeve-seat subassembly. According to another embodiment of the invention, the elongate sleeve is permanently interconnected with a nose tip to form a sleeve-nose tip subassembly, an upper housing is positioned about the sleeve-nose tip subassembly, the nose tip housing is thereafter secured to the upper housing, then a valve stem is positioned between the valve body and the sleeve-nose tip subassembly.
It is a feature of the invention to provide an improved fill valve with at least a body, a housing, a sleeve, and a nose tip that may be integrally connected by two or more flared portions for preventing the escape of propane and enhancing safety during use of the fill valve.
Yet another feature of the invention is a fill valve which may be manufactured at a relatively low cost and which is highly reliable.
It is an advantage of the invention that the lower stem may include an alignment mechanism for substantially aligning the lower stem within the flow passageway in the elongate discharge nose of the fill valve. The lower stem may be provided with one or more alignment pins which slidably engage the interior surface of the passageway in the elongate nose when the handle moves between the opened and closed positions.
It is further advantage of this invention that the fill valve may be used is conjunction with existing control valves of the type conventionally mounted on propane tanks. It is estimated that several million such control valves are in operation. Accordingly, the fill valve of the present invention significantly reduces the discharge of propane to the environment but does not require modifications to the conventional control valve. In another embodiment, the fill valve is designed for use with a newer type of control valve having external threads and a check valve.
In the further advantage of the present invention that the fill valve may be manufactured at a cost which is not significantly greater than prior art fill valves, although the fill valve of the present invention has a significant advantage of reducing the discharge of propane to the environment.
These and other objects, features and advantages of the present invention will become apparent from the following detailed description, wherein reference is made to the figures in the accompanying drawings.